In view of the modern trend to increasing the area of the windows of motor vehicles and arranging the windows of motor vehicles in increasingly sloping positions in order to achieve satisfactory aerodynamic performance, it is becoming more and more necessary to provide a blind arrangement in the region of the rear window of which will protect the necks of the passengers in the back seats of the vehicle from the effects of sunshine. Blinds which can be used for that purpose are typically in the form of a roller-type blind comprising a housing which is generally fixed to the rear window shelf of the vehicle, the housing having a guide slot through which extends a strip of flexible material of which one end is fixed to a straight winding member disposed within the housing. One end of the strip of material extends to the outside of the housing through the slot and is fixed to a pull bar member which is also straight and which, in a retracted position of the blind in which the strip of material is disposed within the housing, closes the guide slot relative to the exterior.
In addition however, further to enhance the aerodynamic performance of a motor vehicle, automobile designers have a tendency at the present time to arrange for the windows of a vehicle to be of a generally curved configuration. In that situation however the above-discussed roller blind in which the strip of material which is unwound from the housing of the blind is disposed in a plane and is therefore flat, is poorly suited to use in relation to a curved window. More specifically the blind cannot closely conform to the curved configuration of the window by virtue of the difference in curvature between the window and the flat blind. On the other hand the pull bar cannot conform to the shape of the top edge of the window assembly so that, even when the blind is in the extended position, there is a gap between the blind and the edge of the window, through which sunshine can pass and thus cause difficulties for the passengers in the rear seats of the vehicle.
While it has been envisaged that the pull bar of the roller-type blind discussed above may be curved in order to conform to the shape of the upper edge of the window assembly to be covered by the blind, the curve of the upper edge of the window assembly is of a complex configuration which has both curvature in the plane of the window and curvature in a plane which is inclined with respect to the plane of the window. Moreover the guide slot provided in the housing of the blind is generally arranged in one plane so that it is deemed that a pull bar which would conform to the shape of the upper edge of the window would not coincide with the guide slot when the blind is in a retracted position. That is considered to be a major disadvantage as the pull bar must be capable of fitting into the guide slot in the retracted condition of the blind in order for the blind in the retracted condition to be entirely contained within the housing in order to protect it.